Pressure loaded pump lubricating means



May 12, .1959 F. c. HA BERLAND 2,335,965

I PRESSURE LOADED PUMP LUBRICATING MEANS Filed March 21, 1955 2 Sheets-Sheet 1 May 112, 1959 F. c. HABERLAND 2,885,965

PRESSURE LOADED PUMP LUBRICATING MEANS I Filed March 21, 1955 2 Sheets-Sheet 2 United States Patent-O a abs for 'ErederickufihristiantHaberland, fileveland flhio, assign!!! 1 I I ITIEIQM 'i x ntio t e at s .a e Puma an m re p ic la waeearnu PIQ t p q ins n si r Ilo' de bushin s p ndbeing referredto as pressure loaded pumps;

t. p ssu o des tpumps 9 t e pejinq d g a, S t x l m a l Press re o dablel us iuss wendrlst apar o t i fl s arse P s re ene at dt ythe 12. 1 1

i c mu i to the tear o mo i .pressu e ac .fot t e. axi ytmovabl bushi s ur lth bushin m sealing ela i ns p wit ij h as oc a d ear de- ,scribed injUnitedj StQatesjRatentj No; 2,42Q,'6 22 t John j-;,L u. ki aL,

t b f l yv selectin th relati e areas 9 t e i ward .o r bus ings 1t; 18 pos bl w t szQn r W th e t e l p 1 1iv ts heact a ealingfpressur e t blish -immunriatwn o t-th "p, p (itearunum gs 11 ct d ar ipapablejof, deli .with consi ab vo um umpsof this ype "gene al y incl de a. p t fn n erme h n seat ea hn yin n axially te ins sha t iou nal i n ha e formed n. th bush n and he ge r r. m i e smiesze t such pumps ometime tea s: ,jo tt euhi IQ ZlIiQI B pee s of ea s; ii h ov rQQ r stio al forcestand .pi eye it .e swun an .lhumiugcou lo t t e. shaf man lut t' u n j l' lsltell tithe shafts, are, fitted into the bushling b s so that some aloft the; fluid.under pressure dev iouma n tthelen ht fth t a -1 e fo es rab erw t V t e Pu p in tzvsueh amanner that fluidvundep pre willbetorced a on t le gth of the.. sha i h1 .t e shi lbg e .so as to insure the proper lubric ation of the journakand m re efiective yt verco t ifr t qn lp om i a d p9 itively prevent thescoring and burnin put of the'l shaf ts hand the bushings; Therefore, it isfthe principle object mofttthis inventiont provide a pump constructed in a e a Wit n t e bu n jbort s. flAnother object'of fth'einvention is to provide a pump with means defining a communication betweemthe pump "chamber and the gear' shaft journals whereby fluid under pressure is forced -alongthe length' of'the gear shafts, so

as toprovide lubrication-therefor.

A still further objectof this invention is'toprovide an intermeshing geartype pump having. bushings associated :there,with and including means formed in tthe gear-jengag- .ingrfacesof the bushings cooperative-withthe inteign esh bus i g wi e o m d there n moper ti wi :jthe .intermeshing pump, gears and v functioning tol direct t a flow of fluid under pressure to the gearshaft journals,

vthereby providing a positivedub ricating"system for the in journals. i

A -more'specific'objeet of' the invention is to provide j a t at 50 mann r w re y vf u i un pres ure is time .al mn lh 2,885,965 retreat d Marten "Th se" andgother objects; features and advantages of {the invention will become apparent fromthe following detailed description and" drawings, in which: *Figure is'Ya longitudinal seetional viewnof a .pump

-F1gure 2 is a cross sectional view taken on line-i2---2 Lon-Figure I and showing toadvantagelpunip bushings constructed in accordance with the tprinciple'slof thisjinv'enti'cirij t W l igure B is a greatly enlarged partial ;viewishowing ..;the int'ermeshing g'ean teethof azpump constructed intac ciordance 'withfthis invention, a said gear. teeth theing' tshowngin ne pumping position, and illustrating one embodiment 'of thep'umpbushingsj i Figure 4 is agreatlyaenlar ged tpartiallview similan t0 Figure: B shoWing the intermeshing. gearsmin Ja'ndther pumpingjpositionjr t 1 t t j 5 Figure S is a-greatly enlarged ,part-ialtjviewi similar. to "Figure 1 3 showing themintermeshing pump. gears, in .one pumping position and sillustrating anothetjaembodiment the-pumpbfishings;,.and i i u t Figures. 6 and-fliware. greatly enlarged. partial views similar/ to FigurerS. sho winga-thet intenneshing tgEIB 'SJi a second and a" third .pu'mpiiig position.- respegtivfi yfi l hea samei referencelcharacters are. 'employedito uglier 1 to he sam'e parttini the;various viewsiofttherdrawing.

Referring; now toftthe; drawings; 1Q denotes s i ah chamberedlplimphousin gtrin whicharejrqt ab 1 I a idniventgearsll ,and .an. intermshing dl Yi i ,t fili Driven :gear't11 is supported, on a shaft 13 journaled itsrirightt end, through agflanged, pressur axi-ally movable bushing or end plate 14 and 1 side through a. fixed,,flauged,,b0dy bu ing 9 @hi Plat .515. -Thengearlllmandt-bushings 14;an are an w in afirst chambenlfilformed, in the vp ump ho mg w th t sufficient clearance. between the right, end of the, bushing 14uandithe adjacent t wtallg ofi thehousing to permit anial movement of the bushing 14.-

In a similar. manner drivting,- gearelz has; disposedon titsgright; side a flarifged pr'essure Lresponsive, axiallyt movable ,bushing. 17 an igen 1 ts i. left a fixed, lflangedybody bushing 18.;Drivjng 51 1a n 19, upon which 1 gear 112 is ;;mounted,. is journaled through bushingszlltand- 18and.rriayjmeisuitably cqnne e d to any rsuitabletdriving means; (not: shown) 11 .Gearglz and; as-

fchamben20iformed in the housing intersecting and p rallrzlelttoi chamber .16.- Suflicient clearance 1is i provide beii-tweenitheright end ofthej-rbushing 17 and the adjacent vwall lof theirho usingr tonpermin axial movement {0 the .wb'ushing17. l i

c.-As :willabe observed, the- ,bushings, are tillustratedas niormedwith 1a flat chordal meeting surface therebyjformit .ing a juncture between corresponding ones I of the bush wings However, one, piece fixed,.-t and one jpiece axially .movable bushings. may be employed; without departing from.,the,scope-; of .the invention.

As shown .in'; Figure 2; of Lthe drawingtmthenhousing whastan inlet port or conduit 21 formed jon itsqigh t side and an outlet porttor c onduit zz formed on its left side. --Lowtpr.essure fluid is introduced in the tpump housing jat the! inletv21 and; high pressure fluid is-dischargedfrom iatheihousingthrough outlet 22, the inlet and putlet'. ports Lcommunicating with the inlet and discharge ,a t hs ofithe p p gears; pr s ur -.1oa ab b h n s minp m'ally fittedyinto the bores with suflicient cleagance to i permit g t a i t mov ment o t gthughiy ges'ociated bushings; :17 ;.and M18 are locatd in a lsec ond 'in the peripheries of those bushings on the discharge side of .the pump at the point of convergence of the bushings. Areas 23 and 24 cooperate with the adjacent walls of the housing bores 16 and 20,'respectively, and with the peripheries of the associated bushings to define pressure loading chambers 26 and 27, respectively. The passage 25 extends'from the discharge side of the gears to the right, as viewed in Figure 1, through the inner communi -cating portions of the pressure loading chambers 26 and 27 at their point of juncture. Escape of pressure rearwardlyfrom. the pressure loading chambers is substan- 'tially prevented by means of a suitable O-ring seal (not shown) disposed about the periphery ofthe rear or barrell portion of each bushing in a suitably formed groove in the periphery of the bushing or in the adjacent bore wall. Pressure leaking past the O-ring seal may be vented 'to inlet pressure or to a. zone of intermediate pressure in line with conventional pressure loaded pump practice. Further details of the O-ring seals are found in the aforementioned Lauck' et al. patent. While the bushings have heretofore been described as being flanged bushings it is obvious that bushings having a uniform outer diameter may be employed. To provide an initial sealing relationship between the bushings and gear side faces, coiled compression springs 28 and 29 are disposed within the right end of the chambers 16 and 20, respectively, so as to seat against the terminal end of the barrel or tubular portions to urge the forward surfaces of the bushings into engagement with the gear side faces.

As in the usual pressure loaded pump, constructed in accordance with the teachings of the aforementioned Lauck et al. patent, recesses 30 and 31 are formed in the radially inner portion of the forward or gear engaging surfaces of the pressure loading bushings 14 and 17, or in the gearv side faces, and these recesses are placed in communication with a pressure lower than discharge pressure generated to the pump through the clearance between the gear journals and the bushing bores, or by specific grooves or channels extending axially of the inner cylindrical surfaces of the tubular part or bore of the bushings. area of the pressure loading bushings, the area or size These recesses control the eifective pressure of these relief recesses being determined in any particular pump, so as to control the effective pressure areas of the bushing in such a manner that axial forces resulting from the pressure generated by the pump acting against the gear side face engaging surfaces of the bushings 14 and 17 tending to produce axial movement of the bushings away from the gear side faces, are effectively controlled and overcomeby oppositely directing the loading forces communicated to the rear or motive surfaces of the bushing which latter axial forces are made to slightly exceed the first-mentioned axial forces and thereby maintain proper sealing engagement. Also the bushings 15 and 18 are formed with recesses 30 and 31', respectively, corresponding to the recesses 30 and 31 of the bushings 14 and 17, respectively. Such recesses may be likewise provided in the gear side faces.

Reference is now made to Figures 2, 3 and 4 of the drawings, Figure 2 showing the pump bushing constructed in acco'rdance with one embodiment of this invention and Figures 3 and 4 showing enlarged portions of the intermeshing gears in different pumping positions and the bushingsconstr-ucted in accordance with this one embodiment. The axially movable bushings 14 and 17 are shown with grooves 32 and 33, respectively, formed in their gear engaging faces. These grooves 32 and 33 eflectively direct fluid under pressure to the recesses 30 and 31,. respectively (if such recesses are formed in the bushings) and thereby to the gear shaft journals for positive lubrication thereof. Each groove intersects its associated recess at one end and at the other end extends to a position short of the juncture of the bushings wherein it opens into a pocket formed between the intermeshing gear teeth in certain pumping positions thereof. Groove 32, formed in the bushing 14 associated with the driven gear 11, is directed at an angle a with respectto a line perpendicular to the axes of the gears, and as, groove 32 progresses inwardly of the pump, i.e., from left to right as illustrated, it slopes toward the inlet side thereof. Groove 33, formed in the bushing 17 associated with the driving gear 12, is directed at anangle b with respect to the aforementioned line perpendicular to the axes of the gears, and as groove 33 progresses inwardly of the pump, i.e., from right to left as illustrated, it slopes oppositely to that of the groove 33; that is, toward the outlet-side thereof. As is obvious from the drawings, the angle a is smaller than the angle b, the purpose of which will be described.

Figure 3 shows the'intermeshing gear teeth in one pumping position wherein the gear teeth initially contact each other at the pitch point 34 and the driving point 35, these points lying on the pressure angle line of the gears; and thereby sealing olf from discharge a certain amount of fluid trapped between the points of contact comprising what will be referred to as'pockets 36 and 37 with a slight opening between the gear teeth at 38, so that a fluid communication will exist between the pockets 36 and 37. As the gears rotate, the fluid so trapped is squeezed between the gear teeth because of the decrease in the space as the teeth approach full meshing position, resulting in the trapped fluid being placed under pressure. As the gear teeth approach full meshing position, the pocket 36 and the groove 33 will communicate with one another and a part of the fluid under pressure thus trapped in the pocket 36 will be forced into the groove 33, to the recess 31 in the face of the bushing 17 and thereby tothe associated shaft journal. Continued rotation of the gears toward their full meshing position will cause the groove 32 and the pocket 37 to communicate with one another and the remaining fluid thus trapped will be forced into the groove 32, to the recess 30 in the face of the bushing 14 and the associated shaft journal.

In this embodiment, the angle a is smaller than the angle b. These angles being so chosen that fluid is forced to the groove 33 in advance of that to the groove 32. If the angles were not so chosen, extremely high pressures would build up in the communicating pockets as the gears approach full meshing position and the result would be a forcing of the greater amount of fluid to the groove 32. The opening of one in advance of the other as the gears approach their full meshing position,

. results in a substantially even flow of fluid to the gear journals. Further, large pressures being build up in the space between the gear teeth results the driven gear 11 to be thrown against the drive gear 12 since the resulting high pressures would be larger than discharge pressure causing a severe backlash of the gears.

As the gears continue to rotate in the directions indicated by the arrows there will be succeeding communicating pockets existing between the intermeshing gears, corresponding to the pocket identified on the drawings as 36 and 37, and as each of the corresponding pockets communicate with its corresponding groove, the trapped fluid willbe forcedinto the groove and thereby to its associated recess and gear journal. .As the gears further continue to rotate both of the grooves will be sealed-off and Figure 4 shows the gear teeth in such posi- 3 tion. It should be obvious that the forced lubrication of the gear journals by their corresponding grooves will be intermittent but because of the high rotational speed of assume the gars iniiump applications thdresulting flew rena willhesubstantially contin uousw i ln -pumps ofi-this typerwherein there is developed a very high fluid pressureg a -serious problem-arises because of flu'id' trappedby-thegear-teeth"adjacnethe outlet side of the pump; since such trappedfluid results in a noisy pump operation. 1 In -s11ch pumps-,--it has been found advisable and de'sirable toreduce-the tnoisewaused; by the trapp ed fluid; thisbeing a complished} by providing at-least one of the'bushingswith a groove -formed in the gear engaging face thereofiforkthe reliefot thetrapped fluid; Such a groove is formed in the-bushing adjacent the-outlet side of .the pump-and is commonly known as-an= anti trapping groove. c c

Figures "5, 6 :and 7 i the dr au iiigs'. illustrate a pump incorporating an anti trapping greove in onerof-the *bushin'gs*,+ andas herein illustrated, the-axially movable hush ingrassociated withthe drivei gear is so f orme'd with an antistrappingzgroove-40r AIn this embodiment the antitrapping groove 40uis so formed anddisposed -to be-ef festive =to= relieveronly a portion-of the fluicl -'-tr'apped between the. intermeshing gear teete -as --they approach their :full meshing position, The groove 40,= =as -i1lustrated; isishallow in depth and is similar-in outline to a finger.- I It iSiinClill'CdxfrOmAhG oufllet toward'the inlet side" of the pump, and soldisposed as to he closed oii from the space between.theg'gear teeth hereinafter -describedbefore the lubricating grooves: communicatewith --the space.- i

Lubricating grooves 41 and 42 are formed in i the gear engagin-gwfaceuof the bushings 14 and 17,* respective1y,

and are disposed in a similar @fashion to thecorresponding. grooves -32 and 33=-of--the Figure ae'mbodimenta The groove-41 is disposed -at an angIe a' we -the axis A of the gear ll-and the groove 42 *is dispos'ed at an angle=l *with respect to the axis 'of' the gear 12: 1 In a similar manner to the Figure 3 embodiment; the grooves are so disposed with respect to the gear teeth so that they communicate with-a :space between thew gear teeth; to Abe-hereinafter described; when l the trappedfluid is I under pressure: q

As" illustrated,the intermeshing gear-teeth are in contact at the pitch point 43 and the-driving point-44, these pointslying: on thepressure angle line of the gears =thereby sealing-off from discharge a certain amount of trapped fluidhbetween-the-points oftcontact in-what will be referred to r as pockets 45 and 46 adjacent-theoutput side of the pump, with 'a slight openingbetween the pockets at 47 so -thata fluid communication will exist between the pockets. As thegears-rotate; the fluid so trapped is squeezed between the gear teeth because of the decrease inthespace as the gears approach full meshingposition, resultinginthe-trapped fluid being placed under pressure. As the gears approach full meshing positioni the groove 42 will "communicate-with*the pocket 45 and slightly thereafter, -or -atthe same moment, the groove 41 will communicatewith thepocket 46g so that-each ofthe" associated gear shaft journals" will be lubricated in a manner similar-"to that-- described with reference to the Figure 3 embodimentw ln this -embodiment *the angle a' is -largen than the angle b; however, the uppergroove 42" will communicate with-itsassociated'pocket in advance of the; low'er groove 41, for the same reasons as set forth-in the Figure-3' emgrooves will be no longer in communication with their respective pockets as illustrated in Figures 6 and 7.

In this embodiment; as in" the Figure 3 embodiment, the fluid forcing action willbe cintermitterit, i but because of thehigh rotational speeds of the pump gears, it .will be substantiallycontinuous. a

l i i it i It is to be presslyunderstood that lubrieatinggrooites asfthus dese bed-may befand usually aresim ilar y die posed- -in the fixed--bushings to insure proper 1 biication of the-gear shaft journalsassociated therewith h Lubrieat inggroovesas taughfi bythis-invention are equally appli cable in bushings; of fixed bushing- 'purnps-aswell-fasfin pumps wherein'part of the pump" housing "c onstitutes'the pump/bushings. c t i Thus;there hasbeen-described an irnprovedfgear pump having means i whereby thegear shaft journalsare p0 tively and efiectively lubricated duringthepumpingoper ationi the invention being one which effectively 'solvesa problem prevalenbin gear ;pumps--ye'tjis relatively simple,

Whereinthe various parts of this invention have been referred to aslocated in the right or left positionaj-it-yvill be understood; that this" is done solel forthe purpose of facilitating description --and- {that su referenc s-relate onlyjto the relative position" of sush parts =as' shown in the-accompanyingdrawings,

While certain preferred embodiments of-the invention have been specifically diselosecyit is funderstoodj that the invention is not limited-jthereto aswn1any-variations will be readily apparent to thoseskilleddnthe art-Earidjthe invention is to be given its broadest possible interpretation within the terms of the-followingclaiinst 1. "In a liquid pump; an inlet to and an-out1etfrom said pump; a pair of'intrmeshing gears forforcingjliquid from saidinlet'throughflsaidoutlet} each ofsaidf gears being provided with an axially ex'tendingshaft; {an end plate having a front face cooperable withythe-adjacen't side faces ofsaid gears t'o providea pumpingcsealthere with and being provided "with a pair'of spaced bor-eafor receiving said shafts thus formingjge'ar' shaft-journals; and 'means soconstruct'ed and arranged to direct only liquid whichhas become completelytrapped; by thespaces between successive pairs fof intermeshing gear teeth and squeezed thereinby said gear teeth as they approach full meshing relation to said bores to provide lubrication of said journals including means; defining a first g'roovefin said end plate front face extending radially from one of said'bores angularly' toward said outlet relative to a plane passing throughthe rotational axes 'of said shafts,-- and meansidefining a second groove in said* end plate==front face extending radially from ;the other of said boresangularly toward said inlet relative to said'planegsaid mearis defining said groovesibeing in intermittent communication with'said spaces betweenthe gear teethfas'fsaid gears approach full meshing position.

larity of said meansdefining said first grooveis greater than that of said means defining said second groove.

3 A pumprasrecited in claim 1;wherein saidfangu larity of said means defining said first groove is's'tnaller than that of said: means defining said second groove, and whereinsaidendplatehas means defining-an anti-trapping groove therein adjacent said outlet so as to prevent a portion of ,said liquid from being trapped in said space 4. Ina pressure loaded liquid pump; an inlet toand an outlet from said pump; a pair of intermeshinggears for forcing liquidpfrom saidflinl et throughwsaid outlet each of said gears being provided with anaxially extending 1 shaft; a fixed bushing having a' front racecooperable with the adjacent] side faces of said gears to, provide a pumping seal therewith; an axiallymovable bushing having a front face; meanslfor pressure loading said axially movable bushing to prc vid'c: a pumping seal between said front face thereof and the adjacent side faces of. said gears; a pair of spaced 'bores -in' each- 0f said bushings to receive said shafts"thus fouming gear shaftjourna1s;-and means so constructed and -arranged to direct only liquid whichhas become completely trapped by the spaces "between successive pairsli of intermeshing gear-teth anda squeezeth tthereingbwsaidzageart teethvafs they approach full meshing relation to said bores to provide lubrication of said journalsinclu ding means defining a first groove in said front face of each bushing extending radially from corresponding ones of said bores angularly toward said outlet relative to a plane passing through the rotational axes ofsaid shafts, and means defining a second'groove in said front face of each bushing extending radially from the other corresponding ones of said bores angularly toward said inletvrelative, to said plane, said means defining said grooves being in intermittent communication with said spaces between the gear teeth as said gears approach full'meshing position. a 5. A pressure loaded pump as recited in claim 4, wherein said angularity of saidmeans defining said first groove is greater than that of said means defining said second groove. I 1 ,6. A pressure loaded pump as recited in claim 4, wherein said angularity of said means defining said first grooveis smaller than that of said means defining said second groove, and wherein atleast one of said bushings has means defining an anti-trapping groove therein adjacent said outlet so as to prevent a portion of said liquid from being trapped in said space.

'7. In a pressure loaded liquid pump; an inlet to and an outlet from said pump; a pair of intermeshing gears for forcing liquid from said inlet through said outlet, each of said gears being provided with 'an axially extending shaft; a pair of fixed bushings each radially co-extensive with said gears and having front faces cooperable with the adjacent side faces of said gears to provide pumping seals therewith; a pair of axially movable bushings each radially co-extensive with said gears and having front faces; means for pressure loading said axially movable bushings to provide pumping seals between said front faces thereof and the adjacent side faces of said gears; each of said bushings having a flat chordal meeting surface thus forming a juncture between each pair and each being provided with a bore for receiving a shaft thus forming gear shaft journals; and means so constructed and arranged to direct only liquid which has become completely trapped by the spaces between suc-' cessive pairs of intermeshing gear teeth and squeezed therein by said gear teeth as they approach full meshing relation to said'bores to provide lubrication of said journals including means defining a first groove in said front faces of one fixed and one axially movable bushing extending radially from said bores therein to a position spaced from said junctures and angularly toward said outlet relative to a plane passing through the rotational axes of said gears, and means defining a second groove in said' front faces of the other fixed and the other axially movable bushing extending radially from said bores therein to a position spaced from said junctures and angularly toward said inlet relative to said plane, said means defining said grooves being in intermittent communication with said spaces between the gear teeth as said gears approach full meshing position.

8. A pressure loaded pump as recited in claim 7, wherein said angularity of said means defining said first groove is greater than that of said means defining said second groove.

9. A pressure loaded pump as recited in claim 7, wherein said angularity of said means defining said first groove is smaller than that of said means defining said second groove, and wherein at least one of said bushings has means defining an anti-trapping groove therein adjacent said outlet so as to prevent a portion of said liquid from being trapped in said space.

10. In a gear pump of the type including a pair of intermeshing gears each being provided with an axially extending shaft, end plate defining means radially coextensive with the gear teeth and engaging the terminal side faces of the gears in sealing relation and being provided with bores for receiving said shafts thus forming journals for said shafts, an inlet leading to and an outlet leading from said pump, andmeans to provide lubrication of said journals comprising, means defining a first groove'in saidend plate defining means extending angularly from a position on one side of a plane passing through; the rotational axes of said shafts to one ofsaid bores, and means defining a second groove in said end plate defining means extending angularly from a position on the other side of said plane to another of said bores, said means defining said first and second grooves being effective to allow only fluid completely trapped between successive pairs of gear teeth as they approach fully meshing relation tobe forced into said means defining 'said grooves and thereby to the respective bores to thereby provide said lubrication of said journals.

11. In a gear pump of the type including a pair of intermeshing gears each being provided with an axially extending shaft, a pair of end plate defining means radially co-extensive with the gear teeth each engaging the terminal side faces of the gears in sealing relation and each being provided with a pair of spaced bores for receiving said shafts thus forming journals for said shafts, an inlet leading to and an outlet leading from said pump, and means to provide lubrication of said journals comprising, means defining a first groove in each of said end plate defining means extending angularly from a position on one side of a plane passing through the rotational axes of said shafts to corresponding ones of said bores, and means defining a second groove in each of said end plate defining means extending angularly from a position on the other side of said plane to the other corresponding bores, said means defining said first and second grooves being elfective to allow only fluid completely trapped between successive pairs of gear teeth as they approach fully meshing relation to be forced therein and thereby to said bores to thereby provide .said lubrication of said journals. 1

12. In a gear pump of the type including a pair of intermeshing gears each being provided with an axially extending shaft; pairs of end plates radially co-extensive with the gear teeth of each gear each having a face engaging the terminal side faces of the gears in sealing relation, each end plate being provided with a bore for receiving one of said shafts thus forming journals for said shafts and each having a flat chordal meeting surface thus fonning a juncture between corresponding ones of each pair; an inlet leading to and an outlet leading from ,said pump; and means to provide forced lubrication of said journals comprising, means defining a first groove in the faces of one pair of end plates extending angularly from a position on one side of a plane passing through the rotational axes ,of said shafts to the bores of said one pair, and means defining a second groove in the faces of the other pair of end plates extending angularly from a position on the other side of said plane to the bores of said other pair, said means defining said grooves intersecting said bores and extending to a position short of said junctures, and being eifective to allow only fluid completely trapped between successive pairs of gear teeth as theyapproach fully meshing relation to be forced into said means defining said grooves and thereby to the associated bores for providing said forced lubrication of said journals.

13. In a pressure loaded gear pump of the type including a pair of intermeshing gears each being provided with an axially extending shaft; a fixed end plate and an axially movable end plate, each of which is radially co-extensive with the gear teeth; means to pressure load said axially movable end plate; each of said end plates engaging the terminal side faces of the gears in sealing relation and being provided with spaced bores for receiving said shafts thus forming journals for said shafts;

an inlet leading to and an outlet leading from said pump; and means for providing lubrication of said journals including, means defining a first groove in each of said end plates extending angularly from a position on one side of a plane passing through the rotational axes of said shafts to corresponding ones of said bores, and means defining a second groove in each of said end plates extending angularly from a position on the other side of said plane to the other corresponding bores, said means defining said first and said second, grooves being effective to allow only fluid completely trapped between successive pairs of gear teeth as they approach fully meshing relation to be forced into said means defining said' sealing relation, each of said bushings having a bore therein for receiving one of said shafts thus forming journals for said shafts and having a flat chordal meeting surface thus forming a juncture between each pair; an inlet to and an outlet from said pump; and means for providing lubrication of said journals including, means defining a first groove in one fixed and one axially movable bushing extending angularly from a position spaced from said junctures and on one side of a plane passing through the rotational axes of said shafts to and intersecting said bores in said bushings, and means defining a second groove in the other fixed and other axially movable bushing extending angularly from a position spaced from said junctures and on the other side of said plane to and intersecting said bores in said last-named bushings, said means defining said grooves being effective, 1 to allow only fluid completely trapped between successive pairs of gear teeth as they approach full meshing relation to be forced into said means defining said grooves to said bores for providing said lubrication of said journals.

15. A pressure loaded pump as recited in claim 14, wherein said angularity of said means defining said first groove is greater than that of said means defining said second groove.

16. A pressure loaded pump as recited in claim 14, wherein said angularity of said means defining said first groove is smaller than that of said means defining said second groove, and wherein at least one of said bushings has means defining an anti-trapping groove therein adjacent said outlet so as to prevent a portion of said liquid from being trapped in said space.

17. Means for providing forced lubrication for the parallel shaft journals of a gear type fluid pump having a pair of intermeshing gears, comprising a first and a second passage defining means each radially extending from one of said journals to a position closely adjacent the full meshing position of said gears effective to direct fluid trapped and sealed off from discharge in pockets between the gear teeth and placed under pressure therein by said gear teeth as they approach full meshing relation to said journals, said first passage defining means defining an angle with a plane passing through the rotational axes of said gears on one side thereof and said second passage defining means defining an angle with said plane on the other side thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,271,970 Wood July 9, 1918 1,634,023 Davison June 28, 1927 1,682,842 Hamer Sept. 4, 1928 1,706,829 Thomson Mar. 26, 1929 1,972,271 McIntyre Sept. 4, 1934 2,391,072 Pugh Dec. 18, 1945 2,471,149 Griz May 24, 1949 2,487,732 Schanzlin Nov. 8, 1949 2,624,287 Ilyin Jan. 6, 1953 2,627,232 Lauck Feb. 3, 1953 2,714,857 Albright et al Aug. 9, 1955 2,718,758 Minshall et al. Sept. 27, 1955 2,735,372 Booth et a1. Feb. 21, 1956 2,756,684 Renzo July 31, 1956 2,775,209 Albright Dec. 25, 1956 

